[LeArc] Forecast Discussion : MLI@ 3/2/03 5:01:56 AM

[learc@mailman.qth.net]

The following weather message is provided by McDonough County E.S.D.A.


FXUS63 KDVN 021108
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
500 AM CST SUN MAR 2 2003

TRICKY TEMP FORECAST OVER NEXT 24 HOURS...PLUS ALBERTA CLIPPER TO
DEAL WITH ON MONDAY MAIN FORECAST CHALLENGES THIS GO AROUND. STRONG
COLD FRONT PLOWING ACRS THE WESTERN CWA ATTM...WITH LATEST SFC
ANALYSIS AND MSAS LOOP INDICATING HEFTY PRESSURE RISES SURGING IN
BEHIND FROPA. CLEARING ALSO RAPIDLY MAKING ITS WAY INTO THE
NORTHWESTERN CWA...AND EXPECT THIS TREND TO CONTINUE ACRS THE
REST OF THE CWA THROUGH THIS MORNING. STIFF NORTHWEST WIND SURFING
INCOMING STEEP ISALLOBARIC RISE...AND LATER VIGOROUS MIXING SHOULD
MAKE FOR A WINDY DAY THROUGH AT LEAST EARLY AFTERNOON. HAVE ADDED
SOME WIND CHILL AVERAGES FOR THE MORNING WHERE APPROPRIATE(MAINLY
NORTHWEST HALF OF THE CWA)...WHERE 20 TO 30 MPH WIND WILL INTERACT
WITH PLUNGING TEMPS INTO THE LOWER TO MIDDLE TEENS. A FEW FLURRIES
MAY STILL BE WRUNG OUT BY STRONG LLVL CAA AND ELONGATED VORT COMPLEX
ALOFT MAINLY ACRS THE NORTH HALF OF THE CWA EARLY THIS MORNING...BUT
PROBABLY NOT MUCH OF A FACTOR. SHORT RANGE MODELS NOW MORE BULLISH ON
STEEP 1000-H85 MEAN LAYER LAPSE RATES ACRS THE EASTERN 2/3'S OF THE
CWA TODAY...BUT FEEL STRONG INCOMING SUBSIDENCE AND DRYING WILL WIN
OUT AND PRODUCE MOSTLY SUNNY SKIES ACROSS MOST OF THE AREA BY EARLY
AFTERNOON. DO THINK THERE COULD BE AN EARLY MORNING CLEAR OUT...WITH
A FOLLOWING CU FIELD REBIRTH IN BUILDING LLVL INSTABILITY BY LATE
MORNING...ALL TO BE MIXED OUT AND ERODED INTO A MOSTLY SUNNY MID
AFTERNOON PERIOD. HAVE REMOVED FLURRIES OUT OF SECONDARY CU FIELD
GENERATION AS FEEL WON'T BE WORTHY OF ZONE MENTION...EVEN THOUGH A
FEW FLAKES MAY DRIFT OUT OF THE QUICKLY PASSING "COTTON BALLS".
INCOMING REALLY DRY SFC DPTS WON'T HELP INSTABILITY FLURRY POTENTIAL
AS WELL. STRONG MIXING POTENTIAL AND SOME EARLY MARCH INSOLATION OVER
PRETTY MUCH A BARE GROUND...WILL BATTLE EFFECTS OF STIFF INCOMING
CAA. HAVE LEANED TOWARD WARMER FWC HIGHS FOR TODAY...OR EVEN GONE
ABOVE GUIDANCE. TEMPS WILL CONTINUE TO TAIL OFF THROUGH LATE MORNING
BEFORE SOME REBOUND EXPECTED DUE TO ABOVE MENTIONED FACTORS.

AS WINDS DECREASE THIS EVENING UNDER LINGERING CLEAR SKIES...SHOULD
BE QUICK TEMP DROP OFF. EXPECT LOWS TO OCCUR AROUND OR JUST
AFTER MIDNIGHT...BEFORE INCREASING HIGH TO MID DECK CLOUDS IN
BUILDING WAA REGIME ALOFT AND SOUTHEAST SFC WIND INITIATES TOWARD
09Z MON.

TURNING ATTENTION TO CLIPPER ON MONDAY...SHORT RANGE MODELS STILL
SUGGEST ROBUST ISENTROPIC LIFT AND CONVERGENT H85-H5 QG FORCING OUT
AHEAD OF IT...TO SATURATE COLUMN AND PRODUCE A LIGHT SNOW EVENT OVER
MUCH OF THE NORTHERN 2/3'S OF THE CWA. SPEC HUMIDITIES...STRENGTH
OF POS OMEGA FIELD OVERLAPPING IN ENOUGH OF A SATURATED 1000-500 MB
LMRH COLUMN...AND OTHER FORCING PARAMETERS AS WELL AS EXPECTED 15
TO 1 RATIOS OF WATER TO SNOW SUGGEST FAR NORTHERN CWA COULD RECEIVE
UP TO 2 INCHES BY MONDAY EVENING. AMOUNTS SHOULD TAPER TO AN INCH
OR LESS DOWN TO THE I-80 CORRIDOR...IF FORCING AND AVAILABLE RH
FIELDS KEEP THERE CURRENTLY PROJECTED TRACK. FLURRIES OR LIGHT SNOW
NOT AMOUNTING TO MUCH ACRS THE SOUTH.  SYSTEM EJECTING OUT OF
SOUTHERN ROCKIES/PLAINS AND ALONG COLD DOME AND BAROCLINICITY...STILL
LOOKS TO MAKE FOR AN INTERESTING TUESDAY.

.DVN...
IA...NONE.
IL...NONE.
MO...NONE.

$$

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